| Count | Meaning | Situation |
|---|---|---|
| 1 | Acknowledgement / attention | Reply to contact, "I see you" |
| 2 | Contact / greeting | Calm presence, near partner |
| 3 | Alarm — threat | Raptor, unknown human |
| 4 | Content / well-being | Safe situation, bonding |
| 5+ | Mobbing — rally flock | Intense threat, chasing raptor |
| 2–3 short | Food | Food find, but kept sparse |
| 2 long | Territorial | Territory defence, breeding season |
Counting: A 2024 study in Science showed that crows mentally plan 1–4 calls before vocalising — one of the few documented forms of numerical planning in birds.
Core principle: Crows are highly social and curious, but also cautious. Build trust gradually. A crow that trusts you will actively seek you out.
⚠️ Never use alarm or mobbing against unfamiliar crows. A crow that classifies you as a "threat" shares that information with its flock. This negative association can persist for months to years and is very difficult to reverse.
Exception: Alarm can be useful if you want to study reaction patterns — but only with crows that already know you well and can see that it is you playing.
Hooded crow (Corvus cornix) vocalisations show measurable acoustic differences between populations. Studies across Scandinavia, Central Europe and the Mediterranean have documented systematic variations in fundamental frequency, call duration and modulation patterns.
Why this matters to you: A crow in your region may not respond appropriately to a recording made in another country. The app includes recordings from xeno-canto — note the recording's country of origin for each XC sound.
Your role: Every recording you make and tag with a location contributes to mapping regional dialects. Share data via the JSON export.
Tip: Always record the crow's response immediately after playing a sound. Comparing the sound you played with the crow's reply is the core of dialect research.
Research at the University of Washington (Marzluff et al., 2010) showed that crows (Corvus brachyrhynchos, likely applicable to C. cornix as well) are capable of individual facial recognition in humans.
The experiment: Crows were trapped by researchers wearing a specific mask. Afterwards, crows reacted aggressively specifically towards that mask — not others. The reaction also spread to crows that were not present during the trapping.
Memory: Negative associations were still observed 5 years later. Positive associations appear to build more slowly but are equally lasting.
Practical conclusion: Crows in your area recognise your face. Always wear similar clothing during contact sessions to reduce confusion. Hats and glasses can interfere with recognition.